RESPIRATORY APPARATUS. 119 



it. Whether cough accompanies the disease or not can usually 

 be learned from the anamnesis, although we can not depend 

 upon this to determine its character. It is always best that we 

 induce the patient to cough in our presence ; this may be done 

 by pinching the upper three rings of the trachea or pressing 

 the finger ends of both hands against the arytenoid cartilages 

 of the larynx. In sensitive healthy horses one or a few short 

 coughs will follow the manipulation, while in indolent indi- 

 viduals there is no reaction. 



Healthy cattle can not be made to cough by simply pinch- 

 ing the trachea, and even those with diseased lungs may fail to 

 react. A better method is to close both nostrils for a minute, 

 which usually has the desired affect. 



If the ox can be made to cough by pinching the upper 

 trachea or larynx, or if coughing takes place in the horse 

 when only slight pressure has been used, some abnormal irri- 

 tation exists. If cough can be readily induced by pressing 

 the lower windpipe, a tracheitis is present. 



The frequency of the cough. A cough may 

 be occasional or frequent, continual or transitory. If the 

 cough is occasional usually only one or a few impulses occur, 

 but when frequent several in succession — a fit of coughing. 



The painfulness of the cough is recognized by the 

 general behavior of the patient, which seeks to suppress the 

 pain by shaking the head and making masticatory and swal- 

 lowing movements. The animal may also be restless, paw 

 and groan. A painful, painless, burdensome, and torturing 

 cough may be distinguished. The cough is painful in acute 

 bronchitis, pleurisy, pleurodynia, and in so-called "whooping 

 cough" of dogs; painless in chronic laryngitis. 



The force of the cough impulse depends upon 

 the vigor of the action of the expiratory muscles and the 

 elasticity of the lungs. Accordingly, the cough may be strong, 

 vigorous, or weak. It is weak if expiration is difficult or if 

 the patient is unable to cough vigorously : reduced, debilitated 



